PROGRAM ERROR :(

well i have photoshop Cs2 and it was working fine until i continuously tried to edit a picture like sharpen it or crop it, and i got a popup saying "Cannot complete command because of program error" and to make the long story short i thought my computer had a virus so i reset my computer to factory settings and reinstalled it. It was working fine for about 2 hours but then it began again. Any help? Thanks in advance :)

edit: i have a windows vista if that matters :]